Objective: To establish a determination method of zinc oxide in compound ethacridine lactate ointment. Methods: Content of zinc oxide in the same batch of compound ethacridine lactate ointment was determined by complexometric titration

and the specificity

linear range

precision and accuracy were analyzed to judge the applicability of the method. Results: The method was specialized. Zinc oxide was linear related in the mass range from 6.0 to 56.5 mg. The linear equation was Y=0.245

196 X+0.050

564 (R=0.999

4). The limit of zinc oxide detection was 0.13 mg

and the quantitative limit was 0.43 mg. The repetitive RSD (relative standard deviation) of zinc oxide in precision experiment was 1.5% (n=6)

with intermediate precision of 1.3% (n=12). The average recycle rate of each additive amount of zinc oxide in accuracy test was 100.3% (RSD=2.7%). Conclusion: The method is simple

rapid

and the results are in accordance with the requirements of general rule 9101 in Pharmacopoeia of People’s Republic of China (2020 Edition)

which is suitable for the determination of zinc oxide in compound ethacridine lactate ointment.